What Causes Nausea Along With Depression And Memory Loss?

Last Monday afternoon, I had a odd wave come over me and then I felt naseaus, but never felt sick. The next morning I woke up, very sad, still having this odd wave of feeling quizzy, it starts at my toes. I became worried and went to call my neighbor and realized I couldn t remember anyone s name. At the clinic I couldn t even remember my street address. My doctor had me have a MRI. The results of my MRI came back with a shadow on the right side. I m having another MRI with contrast tomorrow. What could be causing this? My memory hasn t totally come back. I still have trouble remembering simple steps at work.